Corals reveal El Niño storms are growing stronger
A new US study using chemical records in coral skeletons shows El Niño events have intensified markedly compared to pre-industrial times, as scientists warn an approaching El Niño could be one of the strongest on record.
Scientists are warning that a particularly powerful El Niño may be forming — a natural climate pattern that recurs every two to seven years and affects weather worldwide. In July, the US National Oceanic and Atmospheric Administration recorded temperature increases exceeding three degrees Celsius in the eastern and central Pacific, and Germany's national weather service says the event could become one of the strongest since records began.
Corals as a climate archive
Reliable ocean surface temperature data only exists from the 1980s onward, when satellite monitoring began, leaving a gap in understanding how El Niño behaved before industrialization. To address this, University of Michigan paleoclimatologist Julia Cole and her team studied fossilized and living corals near the Galápagos Islands, publishing their findings in the journal Science. Corals grow one to two centimeters annually, forming ring-like structures whose chemical composition — including the ratio of strontium to calcium and specific oxygen isotopes — records the water temperature at the time of growth.
By analyzing corals covering a little under half of the years in the last millennium, the researchers concluded that El Niño events have become noticeably stronger than in pre-industrial times. Jens Zinke, a paleobiology professor at the University of Leicester, said the findings align with climate models predicting a higher likelihood of extreme eastern Pacific El Niño events in the 2030s. However, other scientists, including meteorology professor Andreas Fink in Karlsruhe, caution that the coral data is regionally limited to the eastern Pacific and difficult to compare directly with modern measurements.
Floods, drought and coral bleaching
A strong El Niño can bring heavy rain and flooding to Ecuador and Peru, while triggering drought and wildfires in Australia and Indonesia, and temporarily raising global temperatures. Thomas Felis, a researcher at the University of Bremen, said that if this event develops into a "Super El Niño," 2027 could become another record-heat year and trigger a fresh wave of global coral bleaching, similar to the events of 2015-16 and 2023-24. Prolonged high temperatures cause corals to expel the algae that sustain them and can ultimately kill the coral, destroying not only a unique ecosystem but also a valuable archive of ocean history.
